1.0 Field of the Invention
This invention relates generally to packaging for a paste-form product, and more specifically to such packaging in the form of a closed storage container with a closable outlet opening on its bottom portion designed to be coupled to a dosing unit.
2.0 Discussion of Related Art
Liquid to paste-form detergents are known. These detergents are generally adapted to meet household requirements which means that they have to be sufficiently liquid so that they can be poured out and dosed without difficulty. Since, in addition, they have to be stable in storage over a relatively broad temperature range, the use of organic solvents and/or hydrotropic additives normally cannot be avoided. Unfortunately, such additives are non-detersive, relatively expensive and take up additional packaging volume and transportation and storage capacity. In addition, the presence of flammable solvents is particularly problematic in that it necessitates additional safety precautions on account of the comparatively high consumption of detergents in laundries. For this reason, detergent concentrates of this type are of only limited use, if any, for laundries.
Accordingly, powder-form detergents is labor-intensive, particularly in large extensively automated laundries, the detergents are generally stored and dosed in predissolved form as stock liquors, i.e. a water-containing concentrate is first prepared and then delivered to the individual washing stations. However, the detergents traditionally used in laundries contain relatively high percentages of washing alkalis which are poorly soluble in cold water and, in addition, lead to xe2x80x9csalting outxe2x80x9d effects. They cause phase separation with the result that the organic components, more especially the nonionic surfactants and soaps, separate and cream up. Accordingly, the stock liquors have to be diluted relatively heavily with water and, in addition, intensively stirred and circulated in a continuous cycle to prevent individual components from being deposited in the feed lines to be washing stations. Consequently, such processes involve high capital outlay on large mixing tanks and the associated mixing and feed systems, and require a constant supply of energy for heating and circulating the stock liquors.
A detergent which meets these requirements is described in EP 0 295 525. This detergent is a paste-form detergent which imposes particular demands on handling for dosing and mixing with water as the solvent. Such detergent pastes are transported and stored in large containers. It is proposed that the storage container be placed in a removal unit above the dosing unit and that the paste be removed downwards. Where a pack of the type in question with a flexible storage container is used, it is proposed that a follower plate be placed on the flexible storage container accommodated in the outer container, this follower plate exerting pressure on the storage container to obtain largely complete emptying of the storage container.
It has been found that the follower plate has to be made very heavy if uniform lowering and substantially complete emptying of the storage container are to be obtained. However, this has the disadvantage that such heavy weights are very difficult to handle which increases the risk of errors in operation. In addition, the heavy follower plate necessitates an overall very stable and hence expensive construction for accommodating the pack.
Accordingly, with the problems of the related art in mind, the problem addressed by the present invention is to further develop packaging for paste-form products in such a way that the storage container can be safely and substantially completely emptied by simple means.
According to the invention, the solution to this problem is to improve prior packaging by making of the flexible storage container thinner in its upper part than in its lower part.
Through use of the aforesaid embodiment of the invention, the subject pack or packaging or storage container can be emptied substantially completely without significant effort by simple means and without any need for aids in the form of a heavy follower plate. This is because, through the removal of product by reduced pressure, the thinner-walled region follows the product towards the outlet opening and adheres or moves closely to the thicker-walled region so that the paste-form product is largely stripped off, thereby providing a function similar to that of a follower plate in a cartridge.
In a preferred embodiment of the invention, the flexible storage container consists of a lower part with relatively thick walls and an upper part with relatively thin walls which are joined closely together. In this way, the pack is easy to make and, for example, by welding together the two bag-like portions differing in their wall thickness.
In order to optimize the emptying process, the upper and lower parts preferable have substantially the same volume. Another volume ratio may also be selected, depending on the product.
In the interests of optimal complete emptying, it is preferred that the walls of the upper part be about three times thinner than those of the lower part, the walls of the lower part being about 0.6 mm thick and consisting of polyethylene or polyethylene blends. The wall thickness can assume other values.